## **520 Chain Size Explained: Pitch, Roller Width & What Those Numbers Mean**<\/p>\n
If you have ever stared at a motorcycle chain spec sheet and wondered what “520” actually means, you are not alone. The **520 chain size** is one of the most common motorcycle chains, yet the numbers confuse many riders. Let’s break it down clearly.<\/p>\n
### **What Does 520 Mean?**<\/p>\n
The number “520” is not random. It encodes two critical dimensions in a simple format. The **first digit** represents the **pitch** in eighths of an inch, while the **last two digits** represent the **roller width** in millimeters.<\/p>\n
– **5** = 5 \u00d7 1\/8 inch pitch = **5\/8 inch (15.875 mm)**
\n– **20** = **20 \u00d7 1\/32 inch? No** \u2014 the last two digits refer to roller width: **20 = 2.0 \u00d7 1\/8 inch? Actually**, the standard convention: last two digits = roller width in **1\/8 inch increments divided by 10**? Let’s clarify properly below.<\/p>\n
### **Pitch: The Most Important Number**<\/p>\n
**Pitch** is the distance between adjacent pins, measured in eighths of an inch. For a 520 chain:<\/p>\n
– **First digit “5”** \u2192 5 \u00d7 1\/8″ = **5\/8 inch (15.875 mm) pitch**
\n– This matches 50-series chains (e.g., 520, 525, 530 all share 5\/8″ pitch)<\/p>\n
Pitch determines how the chain meshes with sprocket teeth. A wrong pitch will destroy your sprockets and chain immediately.<\/p>\n
### **Roller Width & The Last Two Digits**<\/p>\n
**Roller width** is the space between inner plates \u2014 what the sprocket tooth fits into. For 520:<\/p>\n
– **”20″** means **2.0 \u00d7 1\/8 inch? No** \u2014 Standard: last two digits = roller width in **eighths of an inch divided by 10**? Correct rule: The last two digits indicate roller width in **1\/8 inch increments**? Let me state accurately:<\/p>\n
Actually, the last two digits represent roller width in **eighths of an inch** multiplied by 10? Hmm. Let’s do it cleanly:<\/p>\n
– 520 chain \u2192 roller width = **1\/4 inch (6.35 mm)**? No.
\n Real spec: 520 roller width = **6.35 mm (0.25 in)** \u2014 wait, that’s 1\/4″. But 20 would mean 2.0 \u00d7 1\/8″? 2.0 \u00d7 1\/8″ = 1\/4″ = 6.35 mm. Yes.<\/p>\n
So **520 roller width = 1\/4 inch (6.35 mm)**. The “20” = 2.0 eighths = 1\/4 inch.<\/p>\n
### **520 vs 525 vs 530 \u2014 Quick Comparison**<\/p>\n
– **520**: 5\/8″ pitch, 1\/4″ roller width \u2014 lightweight, common on sportbikes
\n– **525**: 5\/8″ pitch, 5\/16″ roller width \u2014 heavier
\n– **530**: 5\/8″ pitch, 3\/8″ roller width \u2014 touring\/heavy duty<\/p>\n
The **520 chain size** is narrower and lighter than 525 or 530, which is why it’s popular for performance bikes.<\/p>\n
### **LSI Terms You Should Know**<\/p>\n
– **Tensile strength** \u2014 how much load before breaking<\/p>\n